1. Field of the Invention
The present invention relates generally to an engine (power plant) suspension device and more specifically to a device which can be interposed between a vehicle chassis and a power plant and which can be electrically controlled in a manner whereby the attenuation of vibration which is applied to the vehicle chassis, is improved.
2. Description of the Prior Art
FIG. 8 shows a prior art arrangement wherein a cylindrical engine mount 2 is supported on a bracket and operatively connected with a power plant (e.g. a transaxle type arrangement wherein the engine and the transmission are combined into a single unit). As will be appreciated from this figure, the mount comprises a cylindrical outer housing 2a and a tubular member 2b which are interconnected by way of an apertured elastomeric body.
However, this arrangement has suffered from a drawback in that the vibration, which is applied to the mount from the power plant, tends to include the resonance frequency of the bracket 1, and thus induces the same to resonate. As a result, the degree of attenuation of vibration transmission between the power plant and the chassis to which the bracket 1 is connected, has not been as high as desired, and has lead to the generation of reverberation noise in the vehicle cabin, particularly during vehicle acceleration.